iOS开发中,通常获取照片的方式有三种,1.直接调用摄像头拍照 2.从相册中选择 3.从图库中选择。 通常使用到的类或框架有UIImagePickerController,AssetsLibrary,PhotoKit(iOS8later)。本篇博客主要讲解UIImagePickerController,其他的后续会讲解到。

UIImagePickerController

UIImagePickerController 是系统提供的用来获取图片和视频的类;

用UIImagePickerController 类来获取图片视频,大体分为以下几个步骤:

1. 初始化UIImagePickerController 类;
2. 设置UIImagePickerController 实例的数据来源类型(下面解释);
3. 设置代理;
4. 如果需要做图片修改的话设置allowsEditing =yes。

数据来源类型一共有三种:

enum {
    UIImagePickerControllerSourceTypePhotoLibrary ,//来自图库
    UIImagePickerControllerSourceTypeCamera ,//来自相机
    UIImagePickerControllerSourceTypeSavedPhotosAlbum //来自相册
};

在用这些来源的时候最好检测以下设备是否支持;

if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
{
    NSLog(@"支持相机");
}
if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary])
{
    NSLog(@"支持图库");
}
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeSavedPhotosAlbum])
{
    NSLog(@"支持相片库");
}

调用摄像头来获取资源

- (void)viewDidLoad {
    [super viewDidLoad];
    picker = [[UIImagePickerController alloc]init];
    //获取照片的类型
    UIImagePickerControllerSourceType sourcheType = UIImagePickerControllerSourceTypeCamera;
    picker.sourceType = sourcheType;
    //设置代理
    picker.delegate = self;
    //是否允许编辑
    picker.allowsEditing = YES;
}

上面只是实例了UIImagePickerController及其属性 在需要获取图片的时候需要弹出窗口调用

[self presentViewController:picker animated:YES completion:nil];

代理中一共三个方法 其中一个3.0 已经废弃了,只剩下两个我们需要用的.
1.当用户选取完成后调用:

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info;

选取的信息都在info中,info 是一个字典:
字典中的键:

NSString *const  UIImagePickerControllerMediaType ;指定用户选择的媒体类型(文章最后进行扩展)
NSString *const  UIImagePickerControllerOriginalImage ;原始图片
NSString *const  UIImagePickerControllerEditedImage ;修改后的图片
NSString *const  UIImagePickerControllerCropRect ;裁剪尺寸
NSString *const  UIImagePickerControllerMediaURL ;媒体的URL
NSString *const  UIImagePickerControllerReferenceURL ;原件的URL
NSString *const  UIImagePickerControllerMediaMetadata;当来数据来源是照相机的时候这个值才有效

1.当用户取消选取时调用:

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker;

UIImagePickerControllerMediaType 包含着KUTTypeImage 和KUTTypeMovie

1.KUTTypeImage 包含:

const CFStringRef  kUTTypeImage ;抽象的图片类型
const CFStringRef  kUTTypeJPEG ;
const CFStringRef  kUTTypeJPEG2000 ;
const CFStringRef  kUTTypeTIFF ;
const CFStringRef  kUTTypePICT ;
const CFStringRef  kUTTypeGIF ;
const CFStringRef  kUTTypePNG ;
const CFStringRef  kUTTypeQuickTimeImage ;
const CFStringRef  kUTTypeAppleICNS 
const CFStringRef kUTTypeBMP;
const CFStringRef  kUTTypeICO;

2.KUTTypeMovie 包含:

const CFStringRef  kUTTypeAudiovisualContent ;抽象的声音视频
const CFStringRef  kUTTypeMovie ;抽象的媒体格式(声音和视频)
const CFStringRef  kUTTypeVideo ;只有视频没有声音
const CFStringRef  kUTTypeAudio ;只有声音没有视频
const CFStringRef  kUTTypeQuickTimeMovie ;
const CFStringRef  kUTTypeMPEG ;
const CFStringRef  kUTTypeMPEG4 ;
const CFStringRef  kUTTypeMP3 ;
const CFStringRef  kUTTypeMPEG4Audio ;
const CFStringRef  kUTTypeAppleProtectedMPEG4Audio;

好了,写了个小Demo,直接上代码了

#import "ViewController.h"

@interface ViewController ()<UIImagePickerControllerDelegate,UINavigationControllerDelegate>

/** imageView */
@property (nonatomic, strong) UIImageView *imageView;

/** imageViewR */
@property (nonatomic, strong) UIImageView *imageViewR;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    self.imageViewR = [[UIImageView alloc] initWithFrame:CGRectMake((self.view.frame.size.width - 100)/2, 30, 100, 100)];
    self.imageViewR.backgroundColor = [UIColor grayColor];
    self.imageViewR.layer.cornerRadius = 50;
    self.imageViewR.layer.masksToBounds = YES; // 裁剪边
    [self.view addSubview:self.imageViewR];

    self.imageView = [[UIImageView alloc] initWithFrame:CGRectMake(16, 140, self.view.frame.size.width - 32, self.view.frame.size.width - 32)];
    self.imageView.backgroundColor = [UIColor grayColor];
    [self.view addSubview:self.imageView];

    UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
    btn.frame = CGRectMake(16, CGRectGetMaxY(self.imageView.frame) + 20, self.view.frame.size.width - 32, 35);
    btn.backgroundColor = [UIColor greenColor];
    btn.layer.cornerRadius = 5;
    btn.layer.masksToBounds = YES;
    [btn setTitle:@"获取图片" forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
}

- (void)btnClick:(UIButton *)button
{
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"选择照片" message:nil preferredStyle:(UIAlertControllerStyleActionSheet)];
    // 判断是否支持相机
    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
        UIAlertAction *cameraAc = [UIAlertAction actionWithTitle:@"拍照" style:(UIAlertActionStyleDefault) handler:^(UIAlertAction * _Nonnull action) {
            UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
            imagePickerController.delegate = self;
            imagePickerController.allowsEditing = YES;
            // 设置数据源类型
            imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;
            [self presentViewController:imagePickerController animated:YES completion:nil];
        }];
        [alertController addAction:cameraAc];
    }
    // 图集
    UIAlertAction *photoAc = [UIAlertAction actionWithTitle:@"相册" style:(UIAlertActionStyleDefault) handler:^(UIAlertAction * _Nonnull action) {
        UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
        imagePickerController.delegate = self;
        imagePickerController.allowsEditing = YES;
        imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        [self presentViewController:imagePickerController animated:YES completion:nil];
    }];
    [alertController addAction:photoAc];

    // 相片库
    UIAlertAction *albumAc = [UIAlertAction actionWithTitle:@"相片库" style:(UIAlertActionStyleDefault) handler:^(UIAlertAction * _Nonnull action) {
        UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
        imagePickerController.delegate = self;
        imagePickerController.allowsEditing = YES;
        imagePickerController.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;;
        [self presentViewController:imagePickerController animated:YES completion:nil];
    }];
    [alertController addAction:albumAc];

    UIAlertAction *cancel = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {

    }];

    [alertController addAction:cancel];

    [self presentViewController:alertController animated:YES completion:nil];

}


- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    [self dismissViewControllerAnimated:YES completion:nil];
}

// 代理方法,获取图片
// 选取的信息都在info中,info 是一个字典。
/**
// info dictionary keys
UIKIT_EXTERN NSString *const UIImagePickerControllerMediaType __TVOS_PROHIBITED;      // an NSString (UTI, i.e. kUTTypeImage)
UIKIT_EXTERN NSString *const UIImagePickerControllerOriginalImage __TVOS_PROHIBITED;  // a UIImage
UIKIT_EXTERN NSString *const UIImagePickerControllerEditedImage __TVOS_PROHIBITED;    // a UIImage
UIKIT_EXTERN NSString *const UIImagePickerControllerCropRect __TVOS_PROHIBITED;       // an NSValue (CGRect)
UIKIT_EXTERN NSString *const UIImagePickerControllerMediaURL __TVOS_PROHIBITED;       // an NSURL
UIKIT_EXTERN NSString *const UIImagePickerControllerReferenceURL        NS_AVAILABLE_IOS(4_1) __TVOS_PROHIBITED;  // an NSURL that references an asset in the AssetsLibrary framework
UIKIT_EXTERN NSString *const UIImagePickerControllerMediaMetadata       NS_AVAILABLE_IOS(4_1) __TVOS_PROHIBITED;  // an NSDictionary containing metadata from a captured photo
UIKIT_EXTERN NSString *const UIImagePickerControllerLivePhoto NS_AVAILABLE_IOS(9_1) __TVOS_PROHIBITED;  // a PHLivePhoto
/
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info
{
    [picker dismissViewControllerAnimated:YES completion:nil];

    UIImage *image = [info objectForKey:UIImagePickerControllerEditedImage];

    // 保存图片到本地沙盒,
    [self saveImage:image withName:@"avatar.png"];

    NSString *fullPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:@"avatar.png"];
    UIImage *saveImage = [[UIImage alloc] initWithContentsOfFile:fullPath];

    // 设置图片显示
    self.imageView.image = saveImage;
    self.imageViewR.image = saveImage;
}

- (void)saveImage:(UIImage *)currentImage withName:(NSString *)imageName
{
    NSData *imageData = UIImageJPEGRepresentation(currentImage, 1); // 1为不缩放保存,取值为(0~1)

    // 获取沙河路径
    NSString *fullPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:imageName];
    // 将照片写入文件
    [imageData writeToFile:fullPath atomically:NO];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end